There is a large installed base of residential load centers which rely on simple thermal-magnetic circuit breakers which only protect branch circuits by the detection of overcurrent conditions resulting in a trip of the circuit breaker and separating its movable contacts. Typical circuit breakers in the home must be reset manually by operation of the circuit breaker handle.
The electrical panel or panelboard, typically known as a “load center” in residential applications, has a main bus connected to individual branch circuits through individual connection points on the bus that are connectable to the circuit breakers for each branch circuit conductor. The branch circuit conductors supply electricity to the various loads within the residence. Because the circuit breakers, sometimes referred to herein simply as “breakers” for convenience, rely on simple thermal-magnetic protection, they may not provide full protection to all electrical malfunctions in the home. As a safety measure it is increasingly necessary to monitor and control branch circuits in the home for arc faults of both of the parallel and series arc types, i.e. combined arc fault interruption (CAFI), and for ground fault interruption (GFI). Protection against all these faults together is referred to as “dual function” protection.
Thus it would be desirable to provide the breakers of basic residential load centers with more protection capability through a simple and economical retrofit process.